The present invention relates to transmitters used in the process control industry. More specifically, the present invention relates to coupling the transmitter to process fluid.
Transmitters are used in the process control industry to measure a process variable of the process. The process variable is used to control the process and, for example, is transmitted over a two-wire process control loop to a control room. Various process variables include pressure, differential pressure, flow, temperature, turbidity and product level.
Various types of process transmitters are known in the art. For example, U.S. Pat. No. 4,466,290 entitled APPARATUS FOR CONVEYING FLUID PRESSURES TO DIFFERENTIAL PRESSURE TRANSDUCER issued Aug. 21, 1984 to Frick discloses a differential pressure transmitter having a two diaphragms which lie generally in the same plane. A flange is used to couple the transmitter to impulse piping. Another type of transmitter uses a process connection which is oriented 90.degree. relative to that shown in the Frick patent. Such a transmitter is shown in FIG. 4 of U.S. Pat. No. 4,833,922, entitled MODULAR TRANSMITTER, issued to Frick et al.
There is an ongoing need for improved flanges and transmitter configurations for coupling the sensor of the transmitter to the process fluid.